CVE-2026-42248: ollama Download of Code Without Integrity Check

Vulnerability summary

CVE-2026-42248 is a critical (CVSS 9.8) Download of Code Without Integrity Check vulnerability in ollama. EPSS estimates a 0.72% chance of exploitation in the next 30 days, higher than 53.2% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 29-04-2026
   PublishedVulnerability first disclosed.
2. 29-04-2026
   Last modifiedVulnerability information updated.

Description

Ollama for Windows does not perform integrity or authenticity verification of downloaded update executables. Unlike other platforms, the Windows implementation of the update verification routine unconditionally returns success so no digital signature or trust validation is performed before staging or executing update payloads, enabling attacker‑supplied executables to be accepted and later executed by the application. Critically, Ollama for Windows performs silent automatic updates, so the malicious payload may be installed automatically without user awareness. Maintainers of this project were notified early about this vulnerability, but didn't respond with the details of vulnerability or vulnerable version range. Versions from 0.12.10 to 0.17.5 were tested and confirmed as vulnerable, other versions were not tested but might also be vulnerable.

• CWE-494Download of Code Without Integrity CheckThe product downloads source code or an executable from a remote location and executes the code without sufficiently verifying the origin and integrity of the code.